A comprehensive study of the development of four neural functions in the visual modality is proposed. These functions are temporal resolution, spatial resolution, sensory fusion and stereoscopic acuity. They will be measured by the objective index of the visual evoked potential to each type of stimulus, using rapid new techniques developed in our laboratory. Infants of ages from one month to one or two years will be studied, to measure the maturational time course of each neural function and determine whether they have differential developmental rates. This information will be applied to the development of the abnormal visual system in the case of several types of amblyopia, to determine how each function is affected in infant amblyopia and to what extent the functions return to normal under the clinical treatment paradigm.